Apparatus and methods for controlling application of a substance to a substrate

ABSTRACT

Apparatus and methods for controlling application of a substance to a substrate involve the use of a functional agent that blocks the substance from or attracts the principal substance to the substrate. The apparatus and methods may utilize ink jet technology to apply the functional agent directly to the substrate or to an intermediate surface. The principal substance may be an ink, a dye, a marking substance other than an ink, or a carrier for any other type of substance.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/229,149, filed Aug. 20, 2008, and claims the benefit ofprovisional U.S. Patent Application Nos. 60/965,361, filed Aug. 20,2007; 60/965,634, filed Aug. 21, 2007; 60/965,753, filed Aug. 22, 2007;60/965,861, filed Aug. 23, 2007; 60/965,744, filed Aug. 22, 2007; and60/965,743, filed Aug. 22, 2007. All of the above listed applicationsare hereby incorporated by reference herein in their entireties.

BACKGROUND

Lithographic and gravure printing techniques have been refined andimproved for many years. The basic principle of lithography includes thestep of transferring ink from a surface having both ink-receptive andink-repellent areas. Offset printing incorporates an intermediatetransfer of the ink. For example, an offset lithographic press maytransfer ink from a plate cylinder to a rubber blanket cylinder, andthen the blanket cylinder transfers the image to a surface (e.g., apaper web). In gravure printing, a cylinder with engraved ink wellsmakes contact with a web of paper and an electric charge may assist inthe transfer of the ink onto the paper.

Early implementations of lithographic technology utilized relieves ofthe image to be printed on the plate such that ink would only bereceived by raised areas. Modern lithographic processes take advantageof materials science principles. For example, the image to be printedmay be etched onto a hydrophilic plate such that the plate ishydrophobic in the areas to be printed. The plate is wetted beforeinking such that oil-based ink is only received by the dampeningprocess).

Conventionally, all of these printing techniques have a similarlimitation in that the same image is printed over and over again. Thisis due to the fact that conventional lithographic printing uses plateswherein each plate has a static (i.e., unvarying) image, whether it be arelief image or an etched hydrophobic image, etc. Gravure printing alsouses a static image which is engraved in ink wells on a cylinder. Thereis a substantial overhead cost involved in making the plates that areused by a lithographic press or cylinders/cylinder sleeves used by agravure press. Therefore, it is not cost effective to print a job on alithographic or gravure press that will have few copies produced (i.e.,a short-run job). Also, conventional lithographic and gravure presseshave not been used to print variable data (e.g., billing statements,financial statements, targeted advertisements, etc.) except in caseswhere such presses have been retrofitted with inkjet heads, albeit athigh cost and slower speeds. Typically, short-run jobs and/or jobs thatrequire variability have been typically undertaken by laser (such aselectrostatic toner) and/or ink jet printers.

Traditionally, many printed articles such as books and magazines havebeen printed using a process that involves a great deal of post-pressprocessing. For example, a single page or set of pages of a magazine maybe printed 5,000 times. Thereafter, a second page or set of pages may beprinted 5,000 times. This process is repeated for each page or set ofpages of the magazine until all pages have been printed. Subsequently,the pages or sets of pages are sent to post-processing for assembly andcutting into the final articles. Such traditional workflow is time- andlabor-intensive. If variable images (i.e., images that vary frompage-to-page or page set-to-page set) could be printed at lithographicimage quality and speed, each magazine could be printed in sequentialpage (or page set) order such that completed magazines would comedirectly off the press. This would drastically increase the speed andreduce the expenses of printing a magazine.

Ink jet printing technology provides printers with variable capability.There are several ink jet technologies including: thermal, i.e. bubblejet, piezoelectric, so called drop on demand systems, and continuousflow systems. In drop on demand systems, tiny droplets of ink are fired(i.e., sprayed) onto a page. In a thermal jet printer, a heat sourcevaporizes ink to create a bubble. The expanding bubble causes a dropletto form, and the droplet is ejected from the print head. Piezoelectrictechnology uses a piezo crystal located at the back of an ink reservoir.Alternating electric potentials are used to cause vibrations in thecrystal. The back and forth motion of the crystal is able to draw inenough ink for one droplet and eject that ink onto the paper. Continuousflow systems employ a continuous flow of ink from the jets, thedeposition of which is controlled by an electric field that diverts inkejected from the ink head into a catch basin to prevent printing.Selectively controlling the electric field permits ink to be depositedon the print medium in desired locations.

The quality of high speed color ink jet printing is generally orders ofmagnitude lower than that of offset lithography and gravure.Furthermore, the speed of the fastest ink jet printer is typically muchslower than a lithographic or gravure press. Traditional ink jetprinting is also plagued by the effect of placing a water-based ink onpaper. Using a water-based ink may saturate the paper and may lead towrinkling and cocking of the print web, and the web may also be easilydamaged by inadvertent exposure to moisture. In order to control thesephenomena, ink jet printers use certain specialized papers or coatings.These papers can often be much more expensive than a traditional webpaper used for commercial print.

Furthermore, when ink jet technology is used for color printing, inkcoverage and water saturation may be increased. This is due to the fourcolor process that is used to generate color images. Four colorprocessing involves laying cyan, magenta, yellow, and black (i.e., CMYK)inks in varying amounts to make a color on the page. Thus, some portionsof the page may have as many as four layers of ink if all four colorsare necessary to produce the desired color. Additionally, the dotsproduced by an ink jet printer may spread and produce a fuzzy image.Still further, inks used in ink jet printers are extremely expensive ascompared to inks used in traditional lithography or gravure printing.This economic factor alone makes ink jet technology unsatisfactory forthe majority of commercial printing applications, particularly long runapplications.

Laser printing has limited viability for high speed variable printing atpresent, because production speeds are still much slower than offset andgravure, and the material costs (e.g., toner, etc.) are extremely highcompared to commercial offset or gravure ink prices. Laser color is alsodifficult to use for magazines and other bound publications, because theprinted pages often crack when they are folded.

Printing techniques have been found to be useful in the production ofother articles of manufacture, such as electrical components, includingtransistors and other devices. Still further, indicia or other markingshave been printed on substrates other than paper, such as plastic film,metal substrates, and the like. These printing techniques may use thosedescribed above to print paper substrates, in which case thesetechniques suffer from the same disadvantages. In other casesflexography may be used, which, like lithography, requires the preparespreparation of plates.

SUMMARY

In accordance with one aspect, an apparatus for printing includes asubstrate, means for jetting a gating agent in a layer having a firstpattern, means for applying a principal substance in a layer, and meansfor transferring the principal substance from the substrate to a printmedium in a second pattern. The layer of gating agent is disposed atopone of the substrate and the principal substance on the substrate, andthe gating agent and the principal substance are applied to the sameside of the substrate. The first pattern and the second pattern are thesame when the layer of gating agent is intermediate the substrate andthe layer of principal substance, and the first pattern and the secondpattern are different when the layer of principal substance isintermediate the substrate and the layer of gating agent.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the apparatus and methods for controllingapplication of a principal substance to a substrate, their nature, andvarious advantages will be more apparent from the following detaileddescription and the accompanying drawings, in which:

FIG. 1 is a side view of a prior art printing system;

FIG. 2 is a side view of an illustrative embodiment of an apparatus forcontrolling application of a principal substance to a substrate;

FIG. 3 is a side view of an illustrative embodiment of an apparatus forcontrolling application of a principal substance to a substrate;

FIG. 4 is a top view of a pattern surface with a character “A” printedthereon using gating agent jetted from one or more ink jet cartridges;

FIG. 5 is a top view of a pattern surface with lithographic inkassociated with the gating agent of FIG. 4;

FIG. 6 is a cross-section along lines 6-6 of FIG. 5;

FIG. 7 is a side view of an illustrative embodiment of an apparatus forcontrolling application of a substance to a substrate; and

FIG. 8 is an illustration of possible output in accordance with theapparatus shown in FIG. 7.

DETAILED DESCRIPTION

One aspect of the present disclosure is to provide a method for highspeed variable printing using a gating agent applied transiently to thesubstrate. This method includes providing a substrate and applying tothe substrate a gating agent composition capable of being jetted ontothe substrate to enable the formation of images on the substrate. Thegating agent composition includes from 0.05 to 3% by weight of anonionic composition having a hydrophilic-lipophilic balance betweenabout 15 and 30. The gating agent composition also may include up toabout 8% by weight of viscosity modifier such that the composition mayhave a viscosity within the range of about 1 to about 14 centipoise. Thebalance of the gating agent composition comprises water. The gatingagent composition may not contain a discernable amount of dye, pigmentor other colorant, and the gating agent may have a surface tension ofless than about 40 dynes/cm.

In yet another aspect, an apparatus for controlling application of asubstance to a substrate involves the use of a gating agent that blocksthe substance from the substrate. The apparatus includes a cartridge anda gating agent contained within the cartridge. The gating agentcomposition may include a nonionic surfactant, a viscosity controlagent, and water.

The apparatus and methods disclosed herein may utilize jettingtechnology to apply the gating agent directly to the substrate or to anintermediate surface. Any agent may be utilized that blocks theapplication of ink as desired. Because the embodiments disclosed hereincomprehend the use of either (or both) blocking and transfer-aidingcompositions, or one or more compositions that have both properties,reference will be made hereinafter to a gating agent that may haveeither or both of these capabilities with respect to a principalsubstance. Specifically, the gating agent may block transfer of all,substantially all, or some portions of the principal substance. Thegating agent may alternatively, or in addition, aid in transfer of all,substantially all, or a portion of the principal substance, or may blocksome portion(s) and aid the transfer of other portion(s) of theprincipal substance.

Now turning to the figures, FIG. 1 illustrates traditional offsetlithographic printing deck 100. In a traditional lithographic process,the image to be printed is etched onto hydrophilic plate 102 to createhydrophobic regions on the plate which will be receptive to ink.Hydrophilic plate 102 is mounted on plate cylinder 104 and rotatedthrough dampening system 106 and inking system 108. Dampening system 106may include water supply 107, and inking system 108 may include inksource 109. The hydrophilic portions of plate 102 are wetted bydampening system 106. By using an oil-based ink, ink is only received bythe hydrophobic portions of plate 102.

If a blanket cylinder is used, such as blanket cylinder 110, the inkedimage may be transmitted from plate cylinder 104 to blanket cylinder110. Then, the image may be further transferred to web 112 (e.g., paper)between blanket cylinder 110 and impression cylinder 114. Usingimpression cylinder 114, the image transfer to web 112 may beaccomplished by applying substantially equal pressure or force betweenthe image to be printed and web 112. When a rubber blanket is used as anintermediary between plate cylinder 104 and web 112, this process isoften referred to as “offset printing.” Because plate 102 is etched andthen mounted on plate cylinder 104, a lithographic press is used toprint the same image over and over. Lithographic printing is desirablebecause of the high quality that it produces. When four printing decksare mounted in series, magazine-quality four color images can beprinted.

FIG. 2 illustrates a printing deck 200, which may include inking system202, plate 204, dampening system 206, plate cylinder 208, blanketcylinder 210, and impression cylinder 212 as known in the lithographicprinting industry. Plate 204 may be entirely hydrophilic (e.g., astandard anodized aluminum oxide lithographic plate). Here, dampeningsystem 106 of FIG. 1 has been replaced with aqueous jet system 214 andcleaning system 216 in FIG. 2.

Aqueous jet system 214 is placed before the dampening system 206 and maycontain a series of ink jet type cartridges (e.g., bubble jetcartridges, thermal cartridges, piezoelectric cartridges, continuousflow cartridges, etc.). The cartridges may contain any number of holes.Commonly, ink jet type cartridges can be found with six hundred pixelsper inch, often arranged in two rows of three hundred pixels per inch.

The aqueous jet system 214 may be used to emit an aqueous solution(e.g., water, ethylene glycol, propylene glycol, or any combinationthereof). As disclosed herein, the aqueous solution may contain, forexample, one or more surfactants, such as Air Products' Surfynol®. Suchsurfactants may contain a hydrophilic group at one end of each moleculeand a lipophilic group at the other end of each molecule. Adding one ormore surfactants to the aqueous solution may improve the surface tensionproperties of the aqueous solution and may serve as an attractant to alipophilic solution, such as a lithographic ink.

The aqueous jet system 214 may be used to place an aqueous solution on ahydrophilic plate in much the same way that a drop of ink is placed on apiece of paper by an ink jet. In some embodiments, the aqueous solutionmay be ejected through traditional ink jet type nozzles (i.e., heads).Such ink jet type nozzles may include, for example, ink jet nozzles ofknown print cartridge units such as those manufactured by HP, Lexmark,Spectra, Canon, etc. In some embodiments, aqueous jet system 214 maysupport variable print speeds and output resolutions. An example of ajet cartridge and jet head is described in Murakami et al. U.S. Pat. No.7,240,998, which is incorporated by reference. Continuous systemsinclude systems that are available from Kodak under the trade nameVersamark.

The aqueous jet system 214 may be used to “print” or jet the image to beprinted, or any portion thereof, on plate cylinder 208. For example, animage controller may receive image data from a data system. The imagedata may represent the image to be printed or the negative image to beprinted. The image data may include variable image data that changesrelatively frequently (e.g., every printed page), semi-fixed image datathat changes less frequently (e.g., every 100 printed pages), fixedimage data that remains static, and any combination of variable,semi-fixed, and fixed image data. Some or all of the image data may bestored as binary data, bitmap data, page description code, or acombination of binary data, bitmap data, and page description code. Forexample, a page description language (PDL), such as PostScript orPrinter Command Language (PCL), may be used to define and interpretimage data in some embodiments. A data system may then electronicallycontrol aqueous jet system 214 to print in aqueous solution the image(or the negative image) represented by some or all of the differenttypes of image data (or any portion thereof) onto plate cylinder 208.

In some embodiments, as disclosed herein, a vacuum source or heat source215 may be positioned next to or near aqueous jet system 214. In someembodiments, vacuum source or heat source 215 may be integrated withaqueous jet system 214. The vacuum source or heat source 215 may be usedto reduce the size of the individual drops of aqueous solution placed byaqueous jet system 214 by blowing, drying, and/or heating the aqueoussolution after it is printed onto plate 204 or plate cylinder 208.Alternatively, any process parameter, including ambient conditions, suchas humidity levels, could be manipulated that could affect the dropformation. The ability to control drop size of the aqueous solution mayimprove the quality of the printed image. The positive image on platecylinder 208 is presented to fountain solution put down by the dampingsystem 206, and the plate cylinder 208 may be wetted like a standardlithographic plate. The image areas provided by jet system 214 acceptink from the inking system 202.

As plate cylinder 208 completes its revolution, after passing the imageto blanket cylinder 210, it passes through cleaning system 216, whichmay remove ink and/or aqueous solution residue so that plate cylinder208 may be re-imaged by aqueous jet system 214 during the nextrevolution (or after a certain number of revolutions). Cleaning system216 may comprise a rotary brush, a roller having a cleaning solution, abelt, a cleaning web treated with a cleaning solution, an apparatus fordelivering heat and/or air, an electrostatic apparatus, or any othersuitable means of removing ink, aqueous solution residue, or both, fromplate cylinder 208. In some embodiments, blanket cylinder 210 may alsohave a cleaning system similar to cleaning system 216 to clean anyresidual material from blanket cylinder 210 after the image has beentransferred to web 218. Also because certain embodiments include fluidsthat are somewhat soluble in the fountain solutions used in lithographicprinting, this solubility will assist in cleaning the variable imagefrom plate cylinder 208.

In some embodiments, plate cylinder 208 may have all of the static datafor a particular print job etched onto plate 204 by traditionallithographic techniques. The aqueous jet system 214 may then be used toimage only variable portions of a job represented by the variable orsemi-fixed image data on specified portions of plate 204.

In other embodiments, plate 204 may not be used. Instead, as isunderstood in the art, the surface of plate cylinder 208 may be treated,processed, or milled to receive the aqueous solution from aqueous jetsystem 214. Additionally, the plate cylinder 208 may be treated,processed, or milled to contain the static data and be receptive to theaqueous solution to incorporate variable data. In these and any otherembodiments herein, blanket cylinder 210 may be eliminated entirely, ifdesired, by transferring the image directly to web 218.

In some embodiments, one or more of plate 204, plate cylinder 208, andblanket cylinder 210 may be customized or designed to work with variousproperties of aqueous jet system 214 or the aqueous solution. Forexample, as is understood in the art, one or more of these plates andcylinders may be specially processed or milled to only accept solutionejected by print heads of a particular resolution or dot size. Theplates and cylinders may also be specially processed to accept certaintypes of aqueous solutions and reject others. For example, the platesand cylinders may accept solutions of a certain volume, specificgravity, viscosity, or any other desired property, while rejectingsolutions outside the desired parameters. This may prevent, for example,foreign agent contamination and allow for one aqueous solution to beused in the printing process and another aqueous solution (withdifferent physical properties) to be used in the cleaning process. Inother embodiments, customary, general-purpose plates and cylinders areused.

In one embodiment, an aqueous jet system may print or jet an aqueoussolution, gating agent, or functional agent with a multifunctionalpotential onto a pattern substrate. In one embodiment, for example, thegating agent may have a bifunctional potential, though any number offunctionalities are contemplated herein. For example, the gating agentmay include one or more compounds each having a multifunctionalpotential or a plurality of compounds each having monofunctionalpotentials. A functional potential or functionality may include, forexample, a functional portion of a compound that may be attributable toa specific chemical moiety and/or structural region of the compound thatconfers attachment and/or repellant properties to the compound, such as,for example, a hydrophilic region, a lipophilic region, an ionic region,and others known in the art. In one present embodiment, a firstfunctionality may confer attachment capabilities to the patternsubstrate, and a second functionality may confer attachment propertiesto one or more principal substances that may be applied thereto.

In another embodiment, a gating agent may include more than onemultifunctional compound where each species of multifunctional compoundhas at least one functionality in common with the other multifunctionalcompounds and at least one functionality that differs from the othermultifunctional compounds. In this example, a first multifunctionalcompound and a second multifunctional compound may each be printed ontoa similar pattern substrate though the second functionalities of thefirst multifunctional compound and the second multifunctional compoundsmay have different specificities for a principal substance that can beattached to either the first or the second multifunctional compound,assuming the principal substance only reacts with one type offunctionality. In another embodiment, compounds having monofunctionalpotentials may interact to form complexes having multifunctionalitysimilar to that of single multifunctional compounds. In this embodiment,the monofunctional compounds may be included in a single compositionthat is deposited onto a substrate at one time, included in separatecompositions deposited simultaneously, or may be contained in separategating agents that are deposited on a substrate sequentially.

One example of a multifunctional compound contemplated herein includes acompound having one functionality that may be hydrophilic and a secondfunctionality that may be lipophilic. The gating agent may be jettedusing in a desired pattern onto a substrate having either hydrophilic ora lipophilic surface, whereby like functionalities amongst the surfaceand the gating agent would associate to attach the gating agent to thesurface and the opposite functionality of the gating agent would berepelled from the surface to render a pattern of the gating agentattached thereon.

A second composition, for example, the principal substance, having alike functionality (for example, hydrophilic or lipophilic) or otherwiseattracted selectively to the second functionality of the gating agent,which is not attached to the surface, and that is repulsed from orotherwise not attachable to the exposed surface of the substrate(through, for example, coating with a fountain solution or fluid) may beadded to the surface by jetting, dipping, spraying, brushing, rolling,or any other manner known to a skilled artisan. Addition of theprincipal substance may render a pattern of the principal substancecorresponding to that of the gating agent, such that the principalsubstance is only attached to the surface via the second functionalityof the gating agent. It is further contemplated that after theapplication of the principal substance, one or more additional steps maybe performed, including, for example a cleaning step, to ensureregiospecific attachment of the principal substance only to the secondfunctionality of the gating agent and not other areas of the substrate.The principal substance may then be transferred to a second substrate,including, for example, an intermediate roller (e.g., a blanketcylinder) from which an image will be transferred to the print medium,or directly to the print medium to render the desired print image in ahighly accurate and clean manner. In this way, selected patterns may bejetted onto a substrate using a gating agent to which a principalsubstance is subsequently attached that then may be transferred to andimmobilized permanently or transiently on a print medium.

Examples of multifunctional compounds contemplated herein includepolymers, having at least one hydrophilic portion and at least onelipophilic portion, such as a poloxamer or acetylenediol ethoxylated.The poloxamer suitable for use can be represented by the formulaHO(CH₂CH₂O)_(x)(CH₂CHCH₃O)_(y)(CH₂CH₂O)_(z)H, wherein x, y, and zrepresent integers from the range from 2 to 130, especially from 15 to100, and x and z are identical but chosen independently of y. Amongthese, there can be used poloxamer 188, wherein x=75, y=30, and z=75,which is obtainable under the trade name Lutrol® F 68 (alternativelyPluronic® F-68) from BASF; poloxamer 185, wherein x=19, y=30, and z=19(Lubrajel® WA from ISP); poloxamer 235. wherein x=27, y=39. and z=27(Pluronic® F-85 from BASF); and/or poloxamer 238. wherein x=97, y=39.and z=97 (Pluronic® F-88 from BASF). Another particular surfactant ofthis type is the block copolymerpoly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) known asPluronic® F-123 from BASF. Other contemplated compounds includeethoxylates, such as polyethylenimine ethoxylate. In addition, atriblock copolymer known commercially as Pluronic® F-127 (poloxamer 407)from BASF for which x=106, y=70, and z=106 may be used. Additionally,poloxamers 101, 108, 124, 181, 182, 184, 217, 231, 234, 237, 282, 288,331, 333, 334, 335, 338, 401, 402, and 403, respectively, may beincluded in the gating agent, to name a few. Acetylenediol ethoxylatessuitable for use include 3,5-dimethyl-1-hexyn-3-ol (Air Products'Surfynol® 61), and/or 2,4,7,9-tetra-methyl-5-decyne-4,7-diol (AirProducts' Surfynol® 104), and Air Products' Surfynol® 400 seriessurfactants: Surfynol® 420, 440, 465, and 485, respectively. TheSurfynol® 400 series surfactants are produced by reacting variousamounts of ethylene oxide with 2,4,7,9-tetra-methyl-5-decyne-4,7-diol(Air Products' Surfynol® 104), a nonionic molecule with a hydrophilicsection in the middle of two symmetric hydrophobic groups. A furthersuitable surfactant includes SILWET™ 7200, a siloxane block polymer,available from OSi Specialties, Inc. (Danbury, Conn., formerly UnionCarbide Organo Silicon Products, Systems and Services). Another suitablegating agent component is BASF's Sokalan®, maleic acid/olefin copolymer.Other surfactants may include polyethyleneimine (PEI) having a molecularweight of around 1200, ethoxylated PEI having a molecular weight around50,000, hexadecyl trimethylammonium bromide (CTAB), polyoxyalkyleneether, poly(oxyethylene)cetyl ether (e.g., Brij® 56 or Brij® 58 fromAtlas Chemicals). Other compounds contemplated may contain a hydrophilicgroup at one end of each molecule and a lipophilic group at the otherend of each molecule.

Additional examples of multifunctional compounds contemplated includematerials associated with the formation of self-assembled monolayers,such as alkylsiloxanes, fatty acids on oxide materials, alkanethiolates,alkyl carboxylates, and the like that can be functionalized to acceptparticulates on one end and attached at an opposite end to a substratesuch as a pattern surface. Other similar multifunctional compounds knownto one skilled in the art that provide suitable functionalities arecontemplated in the present disclosure. Further, gating agentscontemplated herein may include, in addition to the one or moremultifunctional compounds, for example, water, a water-soluble organiccompound, or a combination thereof.

Suitable water-soluble organic components include: alcohols, such asmethyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol,n-butyl alcohol, sec-butyl alcohol, or tert-butyl alcohol; amides, suchas dimethylformamide or dimethylacetamide; carboxylic acids; esters,such as ethyl acetate, ethyl lactate, and ethylene carbonate; ethers,such as tetrahydrofuran or dioxane; glycerin; glycols; glycol esters;glycol ethers; ketones, such as acetone, diacetone, or methyl ethylketone; lactams, such as N-isopropyl caprolactam or N-ethylvalerolactam; lactones, such as butyrolactone; organosulfides; sulfones,such as dimethylsulfone; organosulfoxides, such as dimethyl sulfoxide ortetramethylene sulfoxide; and derivatives thereof and mixtures thereof.

Additional contemplated components in the gating agents include asolvent, a preservative, a gating agent anchor, a viscosity modifier, ahumectant (e.g. propylene glycol), a biocide, a colorant, a scent, asurfactant, a polymer, a foaming agent, a defoaming agent, a salt, aninorganic compound, an organic compound, water, a pH modifier, and anycombination thereof. Some examples of principal substance contemplatedherein include lithographic inks, dyes, colorants, and the like.

Viscosity modifying agents may include polyethylene glycol, propyleneglycol, cellulosic materials (e.g. CMC), xanthan gum, or Joncryl® 60,Joncryl® 52, Joncryl® 61, Joncryl® 678, Joncryl® 682 solution polymersfrom BASF, to name a few. The gating agent may also include athixotropic fluid that changes viscosity under pressure or agitation.Increasing surface tension of the gating agent can also reducespreading. Surface tension modifiers can include poloxamer (e.g., BASF'sPluronic®) or Air Products' Surfynols®, among others. In addition, otheragents may be incorporated in the gating agent composition such asanticurl and anticockle agents, blocking agent anchors, litho inkmodifiers, receiving surface modifier, antiseptic agents, biocides, andpH adjusters and maintainers.

Print media contemplated include any substance that is receptive to aprincipal substance, and include paper, glass, nitrocellulose, textiles,woven materials, metal, plastic, films, gels, and combinations thereof.

In embodiments as disclosed herein, the gating agent may contain from0.05 to 3% by weight of one or more nonionic surfactants, such aspoloxamer, ethoxylated acetylenediol or other ethoxylated surfactants.Such surfactants may contain both a hydrophilic group and a lipophilicgroup and have a hydrophilic-lipophilic balance between about 15 and 30.Preferably, the nonionic surfactants may include 10 to 80%polyoxyethylene. The balance of the gating agent composition may includewater.

The gating agent composition may include a viscosity modifying agent toachieve a viscosity within the range of 1 to 14 centipoises (cP). Morepreferably, the viscosity is set to 2 to 8 cP, and most preferably to 3to 5 cP. In some embodiments, the gating agent composition may furtherinclude a surface tension modifier to reduce spreading. Preferably,surface tension may be set to less than 40 dynes/cm. More preferably, asurface tension of less than 35 dynes/cm may be attained. The surfacetension modifier may include poloxamer (e.g., BASF's Pluronic®) or AirProducts' Surfynols®,® (e.g. Surfynol® 400 series surfactants), amongothers.

In one embodiment, a gating agent may include from about 1% to about50%, or from about 2% to about 40%, or from about 4% to about 25%, orfrom about 5% to about 20%, or about 20% polyethylenimine ethoxylate,from about 50% to about 99%, or from about 60% to about 98%, or fromabout 75% to about 96%, or from about 80% to about 95%, or about 80%water, and optionally polyethylene glycol 400, optionally polyvinylpyrrolidone, and/or optionally propylene glycol. Further, a gating agentmay have a viscosity ranging from about 1 to about 14 centipoises, orfrom about 2 to about 8 centipoises, or from about 2.5 to about 4centipoises for liquid systems that may be applied by spraying orjetting. For other variable application technologies, the viscosity canbe higher, even up to 1000 centipoises or above.

As evidenced by the above description, surfactant block copolymershaving various properties may be used with imaging cylinders havingvarious material properties to achieve an imaging cylinder that has aselectively oleophilic and hydrophilic surface. The physical bondcreated between the surfactant and the imaging cylinder's surface allowsthe imaging cylinder to repeat the same image multiple times or toselectively vary the image in any given rotation of the imagingcylinder. By taking advantage of the material properties of the imagingcylinder and the block copolymer surfactants, a durable, yet variable,imaging system having the quality of known lithographic printingtechniques may be achieved. Further, without wishing to be bound bytheory, it is believed that by using a gating agent contemplated hereinto which a principal substance, such as ink, is attached, splitting ofthe principal substance may be significantly minimized compared toconventional printing systems.

In other embodiments, a litho ink modifier is included in the gatingagent formulation. The litho ink modifier alters a property orproperties of the underlying blocked ink or other principal substance.The litho ink modifier may include magnesium carbonate, calciumcarbonate, mineral oil, liquid asphaltum, powdered asphaltum, burntplate oils, flash oil, cobalt, soybean oil, and lump rosin, amongothers.

In yet other embodiments, the gating agent composition includes areceiving surface modifier. The receiving surface (e.g. paper) modifierfacilitates the transfer of blocked ink or other principal substance tothe receiving surface. The receiving surface modifier may includesurface dusting powders such as metal powders, and cork powder, to namea few. Other examples of surface modifying compounds includepolyethyleneimine and ethoxylated polyethyleneimine (10 to 80%ethoxylation).

As described above, the gating agent may be applied using one or morejet heads either to a plate or directly to a blanket cylinder, then inkmay be applied in a non-selective fashion to the plate or blanketcylinder, and then the ink may be transferred from the image areas onthe plate or blanket cylinder to the web of paper. In the event that thegating agent and the ink are applied directly to the blanket cylinder,the plate cylinder need not be used. Particular printing applicationsthat may benefit include static print jobs (particularly, but notlimited to, short runs), or variable or customizable print jobs of anysize, for example, targeted mailings, customer statements, wallpaper,customized wrapping paper, or the like.

The gating agent may be applied as, for example, an aqueous fluid bybeing selectively sprayed directly onto the substrate or onto anintermediate surface or directly onto the principal substance using ajet device or other precisely controllable spraying or applicationtechnology. An aqueous fluid may generally have a low viscosity and areduced propensity to form clogs, and is therefore advantageous for usewith a jet head. However, the gating agent may also be applied using jettechnology in a form other than an aqueous fluid. Examples include UVcurable systems and non aqueous siloxane systems Further, the gatingagent is not limited to being a fluid at all and may be applied as asolid, for example as a thin film, a paste, a gel, a foam, or a matrix.The gating agent could comprise a powdered solid that is charged or heldin place by an opposite electrostatic charge to aid in the applicationof the principal substance.

As an example, a liquid gating agent in the form of a solvent may beapplied by one or more jet heads to a plate and a powdered ink colorantdispersible in the solvent may be deposited over the entire surface ofthe plate to form a liquid ink in situ in the jetted areas. Powder inthe non-jetted areas may be removed (e.g., by inverting the plate sothat the powder simply falls off the plate, by air pressure, centrifugalforce, etc), thereby resulting in inked and non-inked areas. The solventmay then be jetted onto the areas to be imaged to form liquid ink insuch areas, and the electrostatic charge removed so that the powder inthe non-wetted areas can be removed. In either event, the resultingimage may thereafter be applied to a substrate, for example a web ofpaper.

Any of the systems described herein may be modified to allow formationof different drop sizes of gating agent. For example, ink jet type headsmanufactured by HP may be used to obtain drop sizes on the order of 14picoliters (pl) up to 1200 dots per inch (dpi) resolution whereas inkjet type heads manufactured by Xaar are capable of ejecting 3 pl dropsat 360 dpi but are also able to eject 6 pl, 9 pl, and 12 pl drops. Theresolution of the resulting imaged areas can be controlled throughappropriate selection of the ink jet type head(s) used to apply thegating agent. The systems described herein may be modified to allowformation of different drop sizes of gating agent. In general, a higherresolution grid, that is a grid with 300 dpi or greater, along withmatched drop size improves interaction with blocking ortransfer/collection of the principal substance, such as an ink. Also, asthe dpi of the grid increases, the size of the drops that is mostefficacious generally smaller. A larger drop size is more susceptible toforced wetting of areas to be imaged. This forced wetting can resultfrom merging of adjacent jetted drops when the image is transferredbetween surfaces (such as in the nip area between a plate and blanket)and can cause a decrease in image quality due to a reduction in printdensity. Such forced wetting can be minimized by the addition/removal ofone or more constituents and/or changing or adjusting one or morephysical properties of the gating agent. For example, reducing certainsurfactants may reduce ghosting while utilizing, adding, and/orsubstituting other surfactants may also improve image quality.Alternatively, one could apply an electrostatic charge to a cylinderthat is opposite in the polarity to the charge of the gating agentapplied to the cylinder. The resulting electrostatic attraction mayreduce or eliminate forced wetting.

A still further option is to modulate/control the temperature of one ormore process parameters. For example, one might elevate the temperatureof the gating agent upon application thereof to a surface to improveadherence and facilitate dispensing thereof. Alternatively, or inaddition, the surface may initially be heated during application ofgating agent to control adhesion, drop shape/size, and the like, and/orthe surface may be chilled (or heated) at some point in the process oncethe gating agent is applied thereto so that the viscosity of the gatingagent is increased, thereby reducing spread of the gating agent intonon-wetted areas.

Another example of an apparatus that may be employed to implement thecurrent embodiment is illustrated in FIG. 3. A printing deck 310, mayinclude a principal substance application system 312, a pattern surface314, a pattern surface cylinder 316, a blanket cylinder 318, and animpression cylinder 320, as known in the lithographic printing industry.The pattern surface 314 may be coated with a polysiloxane or othercoating that prevents ink transfer. Further, a cleaning system 322 forremoval of excess and/or old gating agent and principal substance orother contaminants is included (shown here on both the pattern surfacecylinder 316 and the blanket cylinder 318, though more or fewer arecontemplated). An aqueous jet system 324 similar to those describedabove for application of the gating agent is depicted in relation to thepattern surface cylinder 316, though its placement is variable.

Operation of the printing deck 310 is similar to other embodimentsdescribed herein. For example, a gating agent is applied by the aqueousjet system 324 onto the pattern surface 314 of the pattern surfacecylinder 316. A principal substance is applied subsequently to thepattern surface 314 via the application system 312. As the patternsurface 314 meets the surface of the blanket cylinder 318, the principalsubstance is transferred thereto to be further carried thereon untildeposited onto a substrate 326. It is further contemplated that theapparatus may exclude blanket cylinder 318 and thus the principalsubstance would be directly transferred from the pattern surface 314 tothe substrate 326. Alternatively, additional rollers as desired may beadded that may include, for example, additional aqueous jet systems 324,application systems 312, and cleaning systems 322.

FIG. 4 depicts a hydrophilic pattern surface 410, such as an aluminumsurface, of a pattern surface cylinder 412 with a character “A” 414printed thereon using gating agent jetted from one or more ink jet typeheads. The remainder of the pattern surface 410 is free from any addedmaterials and therefore capable attracting and/or attaching otherwater-based substances. In FIG. 5, the pattern surface (not shown) hasbeen primed with a principal substance, for example, a lipophilic ink516 and a hydrophilic fountain fluid 518 in preparation for printing.The fountain fluid 518 serves as a blocking agent for the remainder ofthe pattern surface that has not been printed with the gating agent toprevent the ink from attaching to the pattern surface. Fountain fluidscontemplated herein further may help to solubilize the gating agent toenable easy removal thereof after transfer of the principal substance(e.g., ink). The gating agent, however, attracts the ink via lipophilicportions thereof to cover the surface of the character “A” with ink.FIG. 6 depicts a cross-section of the primed pattern surface 610 of theplate cylinder 612. Ink 616 has attached to the gating agent 614, andthe fountain fluid 618 has filled the intervening spaces to create acontiguous surface of ink and fountain fluid on the pattern surface.Contact of the primed pattern surface with a print material (not shown)or an intervening roller, belt, or other surface would result in thetransfer of the ink with minimal splitting between the pattern surfaceand the new surface.

In a specific application, the high speed variable printing systems andthe gating agent may be used to accomplish blocking or aiding theapplication of the principal substance by removing or blocking orapplying the principal substance in image or non-image areas, removingan aiding agent in non-image areas, preventing the application of theprincipal substance in certain or all areas, changing the physical orchemical properties of the gating agent or principal substance (such aschanging the viscosity or surface tension of the gating agent orprincipal substance) to affect the application of the gating agent orprincipal substance, any combination of the foregoing, or by any othersuitable method.

In yet other embodiments, the amount of the principal substance appliedto the substrate may vary through use of a gating agent in the form of abarrier or a blocking agent with barrier qualities. In such embodiments,the application of the principal substance to the substrate may beblocked either completely or partially, so that the principal substancemay be applied in intermediate levels to the substrate, as the barrieror the blocking agent with barrier qualities allows, effectuating adensity gradient of the principal substance on the substrate inaccordance with desired intermediate levels of principal substanceapplication.

Further embodiments include the gating agent being applied selectivelyto the principal substance on the surface or other substrate, before orafter application of the principal substance to the surface. Forexample, the gating agent may include a material dispersed within itthat is resistant to affinity with the particular embodiment of theprincipal substance used. The gating agent may then be applied to thesurface in non-image areas, with the material dispersed within thegating agent absorbed into and/or received and retained on the surface.The surface may then be passed adjacent a further surface having theprincipal substance disposed thereon, and the principal substance may betransferred to the first-named surface only in those areas which do notcontain the gating agent, as the material dispersed within the gatingagent resists the application of the principal substance to thenon-image areas.

Properties of the gating agent and of the print medium (e.g., using bondpaper, gloss paper, or various coating techniques) may be varied toachieve a desirable interaction between the protective negative imagethat is printed with the aqueous jet system and the print medium. Forexample, if image sharpness is desired, it may be beneficial to choose agating agent that will not be absorbed at all by the print medium.However, if some transfer of ink is desirable even from the areascovered with the output of the aqueous jet system, it may be beneficialto use a print medium that quickly absorbs the aqueous solution so thatsome ink transfer is also able to occur from the covered areas. Stillfurther, increasing the viscosity of the gating agent and/or increasingthe surface tension thereof, and/or using a supporting agent and/orsystem for non-image and image areas, respectively, such that theboundaries between image and non-image areas are maintained can reducespreading, thus improving quality. In particular, manipulating theviscosity of the gating agent to 1 to 14 cP prevents flooding, that isforced wetting that loses the image, including ragged edges and lines,as well as minimizes ghosting, Ghosting may occur when ink migrates to anon-image area of a cylinder or when residual ink or gating agentremains on a cylinder from a prior impression. It is important that theviscosity of the gating agent be maintained at a value less than 14 cPto allow for the gating agent to be emitted from the jet head. Otherchemical and/or materials science properties might be utilized to reduceor eliminate this effect. The gating agent may also include athixotropic fluid that changes viscosity under pressure or agitation.Manipulating the surface tension of the gating agent can also reducespreading.

Still further, surfactant block copolymers having various properties maybe used with imaging cylinders having various material properties toachieve an imaging cylinder that has a selectively oleophilic andhydrophilic surface. The physical bond created between the surfactantand the imaging cylinder's surface allows the imaging cylinder to repeatthe same image multiple times or to selectively vary the image in anygiven rotation of the imaging cylinder. By taking advantage of thematerial properties of the imaging cylinder and the block copolymersurfactants, a durable, yet variable, imaging system having the qualityof known lithographic printing techniques may be achieved.

Another process variable is the substrate itself. In the case of a papersubstrate, a conventional coated stock of appropriate size, weight,brightness, etc. may be used. One or more coatings, such as clay, may beapplied thereto to delay/prevent absorption of principal substanceand/or gating agent. In the case of other substrates, such as a printingblanket, a printing plate, a printing cylinder, a circuit board, aplastic sheet, a film, a textile or other sheet, a planar or curvedsurface of a wall, or other member, etc., the surface to which theprincipal substance is to be applied may be suitably prepared,processed, treated, machined, textured, or otherwise modified, ifnecessary or desirable, to aid in and/or block transfer of portions ofthe principal substance, as desired.

The types and/or physical characteristics and/or chemical compositionsof the ink(s) or other principal substance(s) may be selected ormodified to obtain desired results. For example, by controlling thesurface tension of the ink, color-to-color bleed and showthrough on theopposite side of the paper can be eliminated. As a further example, oneor more ink(s) used in waterless printing applications may be employedtogether with jetted gating agent (whether the latter is aqueous ornon-aqueous) to block or promote transfer of ink from plate to paper. Inthe case of the use of waterless printing ink(s) with an aqueous gatingagent, the composition of the gating agent may be adjusted in view ofthe lipophilic characteristics of such ink(s) so that the gating agenthas a molecular structure that attracts and/or repels the ink(s) asnecessary or desirable. Alternatively, jetted gating agent appliedinitially to a hydrophilic plate may include one or more hydrophiliccomponents that bond with the plate and one or more other componentsthat bond with or repel ink molecules.

As a still further example, a phase change of the gating agent, or theprincipal substance, or both, may be employed to prevent and/or promotesubstance blocking or transfer/collection. For example, gating agent maybe selectively jetted onto a surface, such as a plate, and principalsubstance may be applied to the surface having the gating agent appliedthereto, whereupon the portions of the principal substance that contactthe jetted gating agent may be converted to a gel or a solid.Alternatively, the principal substance may be applied in anindiscriminate (i.e., non-selective) fashion to the plate and the gatingagent may thereafter be selectively applied to portions of the platethat are not to be imaged (i.e., non-image areas), whereupon theprincipal substance in the jetted portions is converted to a gel orsolid. Still further, a two (or more) component gating solution could beused wherein the components are individually selectively applied insuccession where each is individually jettable, but which, when appliedin the same location, react similarly or identically to an epoxy-typeand other chemical bonds such as covalent, ionic bonding, etc., andphysical interactions such as hydrogen bonding, Van der Waals forces topromote advantageous gating characteristics. The principal substance,such as ink may be applied before or after one or more of the gatingagent components are applied. In any of the foregoing examples, asubstrate (such as a web of paper) may be imaged by the plate.

FIG. 7 illustrates another alternative embodiment. FIG. 7 showslithographic deck 1000 as known in the art (e.g., inking system 1002,plate cylinder 1006, blanket cylinder 1008, and impression cylinder1010). However, upstream from lithographic deck 1000, coating system1016 and aqueous jet system 1014 have been installed. In embodimentslike that shown in FIG. 7, a standard lithographic plate may be etchedwith the static information for a given job or may be completely inkreceptive. In one embodiment, a portion of the plate may be reserved forvariable information (e.g., plate 1100 may include one or more variableimage boxes, such as boxes 1102 and 1104, as shown in FIG. 8). Theportion of the lithographic plate that corresponds to the variable imageboxes may be formed to be ink receptive over the entire surface of thevariable image boxes (i.e., when the variable image box portions of thelithographic plate passes the inking system, the entire rectangularareas will accept ink). In other embodiments, the entire plate may bereceptive to ink and the aqueous jet system can provide blocking fluidacross the entire web 1012.

To generate the variable image, a negative image of the variable imagemay be applied in gating agent by aqueous jet system 1014 directly ontoweb 1012. Before web 1012 reaches aqueous jet system 1014, web 1012 maybe, in some embodiments, coated to prevent web 1012 from absorbing thegating agent. In other embodiments, the web 1012 remains uncoated sothat the gating agent applied by the aqueous jet system 1014 can applythe image to the entire web 1012. Thus, when the portion of web 1012 toreceive the variable image makes contact with the portion of blanketcylinder 1008 transferring the ink for the variable image, web 1012selectively receives the ink only in the areas not previously printed onby aqueous jet system 1014. The standard lithographic deck operates asthough it is printing the same image repeatedly (e.g., a solidrectangle). However, web 1012, which is first negatively imaged byaqueous jet system 1014, only selectively receives the ink in the solidrectangle on blanket cylinder 1008 to create the variable image on web1012. Coating system 1016 may be an entire deck of its own for applyingthe coating. Alternatively, coating system 1016 may be any suitablealternative for applying a coating to web 1012 to reduce its ability toabsorb the gating agent. For example, coating system 1016 may include asprayer that sprays a suitable solution onto web 1012. The solution mayprevent web 1012 from absorbing all or some of the gating agent.

In any of the foregoing embodiments, a blanket and plate cylindercombination may be replaced by a single imaging cylinder and vice versa.Further, one or more of the aqueous jet systems, cleaning systems,stripping systems, and vacuum or heating systems in embodiments may beelectronically controlled via data system.

Still further, the nip pressure of the roller(s) and the compressibilitycharacteristic of the roller(s) at which the principal substance isapplied to the substrate may be varied to control image quality as wellas the compressibility characteristic of the nip roller. Also, rolls orcylinders having a textured surface may be used to control theapplication of the principal substance to the substrate, as desired.Still further, or in addition, the volume of the drops of gating fluidcould be adjusted to control the amount of ink transferred into eachcell, thereby affecting grayscale.

A still further option is to modulate/control the temperature of one ormore process parameters. For example, one might elevate the temperatureof the gating agent upon application thereof to a surface to improveadherence and facilitate dispensing thereof. Alternatively, or inaddition, the surface may initially be heated during application ofgating agent to control adhesion, drop shape/size, and the like, and/orthe surface may be chilled at some point in the process once the gatingagent is applied thereto so that the viscosity of the gating agent isincreased, thereby reducing spread of the gating agent into non-wettedareas.

One could further use multiple different liquids dispensed by separatejet devices that, when applied together, create a gating agent that hasimproved adherence and/or viscosity and/or other desirablecharacteristic. The liquids may be applied at the different or sametemperatures, pressures, flow rates, etc.

Yet another embodiment comprehends the use of two or more arrays or inkjet heads for selectively applying gating agent alone, or forselectively applying gating solution to one or more areas of a surfaceand, optionally, ink to one or more remaining areas of the surface,wherein one or more of the arrays can be independently removed andswitched over while the press is running, or, reconfigured (in terms ofposition) for the next succeeding job (e.g., where regionalcustomization is required).

Due to variations in ink tack from print unit to print unit, one mayundertake a successive modification of gating agent characteristics fromunit to unit to effectively optimize ink transfer by each unit. Yetanother modification involves the use of a phase change material tobuild up a printing surface.

In yet other embodiments, the gating agent(s) used to controlapplication of the principal substance to the substrate may becombinations of blocking and aiding agents. In one example, theprincipal substance is disposed on a surface and is covered in non-imageareas by a blocking agent that blocks application of the principalsubstance to the substrate. In image areas, the principal substance iscovered by an aiding agent that tends to establish a bond with theprincipal substance to aid in application onto the substrate.Alternately, the gating agent(s) may be disposed on the surface andcovered by the principal substance. In one example, a lipophilicblocking agent is selectively disposed on non-image areas of the surfaceand a hydrophilic aiding agent is selectively disposed on image areas ofthe surface. The principal substance is then disposed on top of thelayer created by both gating agents. The layer of both gating agentshaving a consistent height on the first surface may prevent migrationbetween the principal substance and the aiding agent. As the surface ismoved adjacent the substrate, the blocking agent keeps the principalsubstance from being applied to the substrate, while the aiding agentallows application of the principal substance to the substrate.

In alternate embodiments, the surface may be a lithographic plate,cylinder, or the like having a portion that may be used for controllingapplication of the principal substance to the substrate by applyingvariable configurations of the principal substance to the substrate. Insuch embodiments, variable symbology, encoding, addressing, numbering,or any other variable tagging technique may be utilized in the portionof the first surface reserved for controlling application of theprincipal substance. The principal substance is first disposed on thefirst surface indiscriminately. Before the substrate is passed near thefirst surface for application of the principal substance, a blockingagent is selectively applied to the substrate in an area where thereserved portion of the first surface will subsequently be movedadjacent the substrate so as to allow the desired configuration, orimage, of the principal substance to be applied thereto. In a moregeneral embodiment, the substrate may be brought adjacent one or morethan one surface having similar or differing principal substancesdisposed thereon, wherein blocking and/or aiding agents are selectivelytransferred to the substrate from the surfaces in the reserved portion.In one embodiment, a magnetic ink is transferred from one of thesesurfaces to the substrate (e.g., a paper web). One or more non-magneticinks may be transferred from the same surface or from one or moreadditional surfaces. A gating agent may be used to either block or aidapplication of the magnetic ink to the paper web in a desiredconfiguration in the reserved portion thereof using any of thetechniques for using blocking and aiding agents described above. Theresult is a printed paper web having markings of magnetic ink (such as aMICR marking or other encoded information) that may be changed fromimpression-to-impression. One example is applying encoded RFID circuitsas part of the variable print process. This eliminates the need for postprinting programming.

According to a still further embodiment, the gating agent is selectivelyapplied to a receiver surface by one or more jet heads and attracts orblocks an intermediate fluid, such as traditional fountain solution,which is applied indiscriminately to the receiver surface but gated bythe gating agent, such that the fountain solution adheres selectively tothe receiver surface prior to application of ink thereto. In thisembodiment, the gating solution is formulated to interact with andcontrol the fountain solution, as opposed to controlling the ink.Additional embodiments may neutralize or compromise the fountainsolution, or selectively enable removal thereof from the receiversurface. In more general terms, these embodiments comprehend the use ofa selectively applied gating solution together with indiscriminatelyapplied fountain solution and ink wherein the gating agent controlswhere the fountain solution is maintained.

As mentioned above, the gating agent may include one or more surfactantsor may be temperature or vacuum controlled to produce drop size andviscosity characteristics that are favorable to produce a high qualityimage. However, the quality of an image may also be affected by aphenomenon known to those of skill in the art as ghosting, which may bean especially serious problem if consecutive images are different.

Ghosting may be diminished by assuring that the image and non-imageareas are clean of ink and/or any gating agents between successiveimpressions. Cleaning the cylinder after every application of inktherefrom as described with respect to any of the cleaning systemsdiscussed hereinabove is one way to assure that the cylinder is clean.The composition of the gating agent may also be engineered to reduceghosting by promoting more complete cleaning by the cleaning system.

Another approach to diminish ghosting is to inhibit the migration of inkfrom the image areas to the non-image areas on the cylinder. Alipophilic solution may be precisely applied to the image areas toattract ink thereto and inhibit migration therefrom. Independently, orin combination with the lipophilic solution, a lipophobic solution maybe precisely applied to the non-image areas of the cylinder to inhibitmigration of ink thereto.

One of the advantages of using the concepts for processing variables andstatic print jobs as described herein is the inherent speed associatedwith a conventional lithographic press. In fact, press speed compared toa conventional lithographic press is limited by the speed at which animage area can be created, which in turn depends upon the method ofcreation of the image area. Such methods have been described herein toinclude application of a gating agent to create the image area. Thegating agent may be a lipophilic or hydrophilic solution, or some othersolution that may have an electrostatic charge applied thereto. Thegating agent may also be an electrostatic charge applied to a portion ofa cylinder. The maximum speed at which any of these gating agents isapplied to one or more cylinders of the press may limit the speed ofoperation of the press.

For most operating conditions wherein an ink jet cartridge is utilizedin normal ink jet printing, the ejection of a droplet from the cartridgeis considered to be an instantaneous event that produces a spot of inkof predetermined size on a target substrate. In reality, the ejection ofa droplet from an ink jet cartridge is not an instantaneous event, butis in fact a transient event, having a beginning, a middle, and an end.If a target substrate is moving at a high speed, the ink droplet maystrike the substrate to form a spot of ink having a tail trailing thespot in a direction opposite to the direction of travel of thesubstrate. This phenomenon, known as tailing, is a direct result of thetransient nature of the droplet generation. Tailing at high press speedsmay limit the effective speed of the press due to print qualityconcerns. It has been found, however, that certain gating agents, whenused with particular jet cartridges may inhibit or alleviate the tailingof the ejected droplets, thereby removing this effect as a limitingfactor on maximum press speed.

The apparatus and methods disclosed herein are also relevant in otherindustries and other technologies, for example, textiles,pharmaceuticals, biomedical, and electronics, among others. Variablycustomizable graphics or text, or a principal substance having enhancedsealing properties or water or fire resistance may be selectivelyapplied to webs of textiles such as may be used to manufacture clothingor rugs. In the pharmaceutical industry, the principal substance may bea drug, a therapeutic, diagnostic, or marking substance other than anink, or a carrier for any other type of substance. In biomedicalapplications, for example, the principal substance may be a biologicalmaterial or a biocompatible polymer. In electronics applications, theprincipal substance may be an electrically conductive or insulativematerial that may be selectively applied in one or more layers on thesubstrate. Other electronic applications include production of radiofrequency identification (“RFID”) tags on articles. Other industries mayalso benefit from selective application of a principal substance to asubstrate. For example, the principal substance may be a thermallyconductive or insulative material selectively applied over components ofan item of manufacture, for example, a heat exchanger, a cooking pan, oran insulated coffee mug. The principal substance may also be a materialwith enhanced absorptive, reflective, or radiative properties, some orall of which may be useful in other items of manufacture, for example,when the principal substance is selectively applied to components of anoven, a lamp, or sunglasses. Still further uses for the principalsubstance may include customizable packaging films or holograms (viaselective filling of refractive wells prior to image forming). Moreover,the technology could be applied to fuel cell manufacturing and theprincipal substance may include functional polymers, adhesives and 3-Dinterconnect structures. In applications for the manufacture ofmicro-optical elements, the principal substance could be an opticaladhesive or a UV-curing polymer. Yet a further application may bedisplay manufacturing wherein the principal substance is a polymerlight-emitting diode material.

Further, in a specific application, the apparatus and high speedvariable printing methods disclosed herein may be used in a number oflithographic applications. For example, the disclosed apparatus andmethods may be ideal for high-quality one-to-one marketing applications,such as direct mailing, advertisements, statements, and bills. Otherapplications are also well-suited to the systems and methods disclosedherein, including the production of personalized books, periodicals,publications, posters, and displays. The high speed variable printingsystems and methods disclosed herein may also facilitate post-processing(e.g., binding and finishing) of any of the aforementioned products.

The following examples further illustrate the disclosure but, of course,should not be construed as in any way limiting its scope.

EXAMPLE 1

A gating agent formulation useful in the present disclosure was preparedas follows:

8 wt % Sokalan® maleic acid/olefin copolymer (95% actives)

1 wt % SILWET™ 7200 siloxane block polymer

91 wt % water

EXAMPLE 2

A second gating agent formulation useful in the present disclosure wasprepared as follows:

30 wt % PEG 200

1 wt % Surfynol® 400 series

1 wt % Pluronic®

68 wt % water

EXAMPLE 3

A third gating agent formulation useful in the present disclosure wasprepared as follows

15 wt % Joncryl® 50

10 wt % isopropyl alcohol

1 wt % SILWET™ 7200 siloxane block polymer

30 wt % PEG 200

44 wt % water

All of the formulations of Examples 1-3 were useful as gating agents andproduced valuable print with a minimum of ghosting, tailing, flooding,or background color.

It will be understood that the foregoing is only illustrative of theprinciples of the systems and methods disclosed herein, and that variousmodifications can be made by those skilled in the art without departingfrom the scope and spirit of such systems and methods. For example, theorder of some steps in the procedures that have been described is notcritical and can be changed if desired. Also, various steps may beperformed by various techniques.

Preferred embodiments of this disclosure are described herein, includingthe best mode known to the inventors for carrying out the disclosure.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the disclosure to be practicedotherwise than as specifically described herein. Accordingly, thisdisclosure includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the disclosure unlessotherwise indicated herein or otherwise clearly contradicted by context.

What is claimed is:
 1. An apparatus for printing, comprising; asubstrate; means for jetting a gating agent in a layer having a firstpattern; means for applying a principal substance in a layer; and meansfor transferring the principal substance from the substrate to a printmedium in a second pattern, wherein the layer of gating agent isdisposed atop one of the substrate and the principal substance on thesubstrate; wherein the gating agent and the principal substance areapplied to the same side of the substrate; and wherein the first patternand the second pattern are the same when the layer of gating agent isintermediate the substrate and the layer of principal substance, and thefirst pattern and the second pattern are different when the layer ofprincipal substance is intermediate the substrate and the layer ofgating agent.
 2. The apparatus of claim 1, wherein the first pattern andthe second pattern are complementary when the layer of principalsubstance is intermediate the substrate and the layer of gating agent.3. The apparatus of claim 1, wherein the substrate comprises at leastone of a printing blanket, a printing plate, a printing cylinder, asheet, a planar surface of a wall, a curved surface of a wall, an etchedsurface, a milled surface, a treated surface, a hydrophobic surface, ora hydrophilic surface.
 4. The apparatus of claim 1, wherein the meansfor jetting comprises at least one of an aqueous jet system, acontinuous flow ink jet system, a thermal jet system, or a piezoelectricjet system.
 5. The apparatus of claim 1, wherein the means for jettingcomprises one or more jet cartridges comprising one or more nozzles. 6.The apparatus of claim 5, wherein the one or more jet cartridgescomprise the gating agent.
 7. The apparatus of claim 1, wherein theprint medium comprises at least one of paper, glass, nitrocellulose, awoven material, a metal, a plastic, a film, a gel, a plate, a circuithoard, a sheet, or a textile,
 8. The apparatus of claim 1, wherein theprincipal substance comprises at least one of a carrier, a lithographicink, a dye, a protein, a nucleic acid, a small molecule, a biologicalsample, a pharmaceutical, a cell, a hiocompatihle polymer, a therapeuticsubstance, a diagnostic substance, a non-ink marking substance, anelectrically conductive material, an insulative material, a thermallyconductive material, a radio frequency identification tag, a hydrophilicportion, a lipophilic portion, a silicon oxide, a metal, a functionalpolymer, an adhesive, a magnetic ink, a 3-D interconnect structure, anoptical adhesive, a UV-curing polymer, a polymer light-emitting diodematerial, water, or a water-soluble organic compound.
 9. The apparatusof claim 1, wherein if the first pattern is the same as the secondpattern, the principal substance is attached to the substrate via thejetted layer of gating agent.
 10. The apparatus of claim 1, wherein ifthe first pattern is different than the second pattern, the jetted layerof gating agent is attached to the substrate via the principalsubstance.
 11. The apparatus of claim 1, wherein means for transferringthe principal substance comprises at least one of an intervening roller,a belt, or a blanket cylinder.
 12. The apparatus of claim 1, furthercomprising at least one of a cleaning system or a sterilizing system.13. The apparatus of claim 12, wherein the cleaning system comprises atleast one of a rotary brush, a roller, a cleaning solution, a belt, acleaning web, an apparatus for delivering heat, an apparatus fordelivering air, or an electrostatic apparatus.
 14. The apparatus ofclaim 1, wherein the gating agent comprises at least one of a compoundhaving a multifunctional potential, a compound having a hydrophilicregion, a compound having a lipophilic region, a compound having anionic region, a compound having a receptor/recognition region, acompound having a paratope, a compound having a specific chemical moietythat confers attachment properties, a compound having a specificchemical moiety that confers repellant properties, a compound having aspecific structural region that confers attachment properties, acompound having a specific structural region that confers repellantproperties, a poloxamer, a surfactant, a solvent, a preservative, ananticurl agent, an anticockle agent, a gating agent anchor, a humectant,an antiseptic agent, a biocide, a colorant, a scent, a polymer, adefoaming agent, a salt, an inorganic compound, an organic compound,water, a pH adjuster, a pH maintainer, a receiving surface modifier, alitho ink modifier, a surface tension modifier, a viscosity modifyingagent, a maleic acid/ olefin copolymer, a polyethyleneimine, apolyoxyethylene, a water-soluble organic compound, or a thixotropicfluid.